Frequency tracking and stabilization of a tunable dual-wavelength external-cavity diode laser

We show a unique dual-wavelength external-cavity laser diode with frequency tracking capability and obtain a stable beat frequency between the dual-wa velength output. By using a Fabry-Perot interferometer as the frequency dis criminator and the time-gating technique in a servo loop, the peak-to-peak frequency fluctuations were stabilized, with respect to the Fabry-Perot cav ity, to 86 kHz in the dual-wavelength output at 802.5 and 804.5 nm, and to 17 kHz in their 0.9 THz beat signal. Similar performance was achieved for t uning of the dual wavelength separation ranging from 0.2 to 4 nm. (C) 1999 Published by Elsevier Science B.V. All rights reserved.